One of the most surreal experiences in my life was riding in an ambulance in Norway and having the EMT sheepishly explain that while the ambulance ride was free, the ER visit was going to come with a bill. He was equal parts embarrassed and indignant about it. The bill was the equivalent of $25.

Others have pointed out siblings, but it’s also worth noting that, in the context of your comment, sisters and brothers is more correct. Sibling is more clinical and might be used in a description like “I have 3 siblings, 2 brothers and 1 sister”. When you are addressing a group, the more familiar brothers and sisters is appropriate. “May the force be with you, siblings” would be very weird.